In today's world, many vehicles are equipped with systems for facilitating remotely controlled vehicle functions such as passive entry and passive starting (i.e., PEPS) of a host vehicle. When a vehicle is equipped with a PEPS system, a user carries a mobile communication unit which can communicate with a base station located in the vehicle. To conserve use of energy stored in its internal battery, system components may remain in a low power state until an initiating trigger (for example, manipulation of a vehicle door handle) awakens one or more other system components. For example, upon sensing that a door handle has been manipulated, the base station may emit a relatively powerful Low Frequency (LF) electromagnetic field, causing a mobile communication unit that is sufficiently close to the base station to awaken. Once the mobile communication unit is awake, it may use Radio Frequency (RF) transmissions to dispatch a response signal, which may be validated by the base station. If the base station recognizes and approves the identity of the mobile communication unit, (i.e., the base station authenticates the mobile communication unit), the base station may facilitate the performance of a predefined vehicle function, such as actuating a door lock mechanism, causing the door to become unlocked.
Because the amount of energy required by the base station to generate a LF field is significant, many such systems employ a sleep mode and awaken only upon the occurrence of a trigger event. Unfortunately, the use of an initiating trigger necessitates that the sequence of authenticating the mobile communication unit be performed within an extremely short amount of time so as to avoid delays in response from the vehicle. Fast-release motors may be employed to perform the actuation functions such as unlocking a door.
An approach of the mobile communication unit toward the vehicle may be detected so that a desire for one or more vehicle functions to be performed may be anticipated and provided in a manner that reduces a perceived delay. Unfortunately, some approaches toward the vehicle are merely incidental, resulting in the occurrence of inadvertent activation of vehicle functions, whereby stored energy is consumed and systems are unnecessarily exercised.
The present invention attempts to address or ameliorate at least some of the above problems associated with vehicle communication systems.